Inductors are considered one of the most common devices in the electronic/electric industry. An inductor is an electronic component designed to provide a controlled amount of inductance. An inductor generally consists of a length of wire wound into a solenoid (i.e., cylindrically-shaped) or toroidal (i.e., drum-like) shape. The inductance may be increased by placing a core with high magnetic permeability within the coil. Suitable core materials include iron, ferromagnetic alloys, and oxides thereof, and mixtures thereof. Commercially made inductors typically have inductance values ranging from less than 2.2 nH to about 10 H. Small inductors are commonly used in radio-frequency tuned circuits and as radio-frequency chokes. Large inductors are employed at audio frequencies.
With the constant demand for miniaturization of essentially every consumer electronic device, manufacturers of inductors are facing a tremendous pressure to minimize the size of inductors, while, at the same time, providing the same or even higher value of inductance, reducing electromagnetic induction interference that may exist with respect to other electronic devices, and minimizing magnetic leakages. At the present time, there does not appear to be a solution that will satisfy all these needs without substantially increasing the manufacturing cost and substantially increasing the complexity of the manufacturing process.